I'm not sure that it's related to Poser's resources management of the gpu-related: it happens to me from time to time, when I've done too many renders with the gpu.
Only once I insisted by just killing Poser without restarting the computer and the card (a gtx980ti) stopped functioning.
Restarting the PC hadn't be enough this time: I had to shut it off by pressing the Off button 4 seconds.
I've encountered this with previous service packs, too.

Yep. Same here, Windows 7 Pro. F**king annoying. Force crash and restart only to find the partially completed render in the cache. There seems to be a disconnect in the status bar where it does not reflect the true condition of the render process.

I have a windows gadget that reflects the activity of the video card: when this situation arrises, the card doesn't compute, at least on my computer.
Furthermore, my gtx is my main card, so that when it's computing, the mouse moves like someone stuck in quicksand. And in that case, everything behaves correctly.

From memory I can't see that I've seen that; my mouse moves normally but the status bar is frozen. There are PLENTY of other 'Poser moments' where the cursor is stuck in quicksand, but I don't think this is one of them for me.
BTW, to be fair, some of those quicksand moments are because I have set up Poser to cane my graphics card... in those situations I expect quicksand.

@piersyf
For me, the quicksand effect is quite normal: my PC has three screens: the main two connected to the gtx and a third connected to the motherboard's video card. And if the gtx is computing, I suppose that I can't expect another behavior.

But when the situation described above happens, everything reacts normally, thus giving the feeling that the gtx isn't computing, while its driver is probably in a bad/wrong state: from my experience, it's better to reboot the computer....

@redphantom
Ah, ok. Mostly I render with aerea.
First I thought It maybe happens when I switch to the Internetbrowser while the render is loading textures and maps. So I always wait till all maps are loaded and the render is path tracing tiles before I do anything else on the PC. But last time it happens anyway.

You people use a Wacom Pen&Touch by any chance and use the pen to activate the render button?
I had same sort of issue with Superfly and found it had to do with my hand holding the pen clicking the button causing mixed commands sent to Poser causing Poser to freeze up while rendering.
I suggested Wacom to add an option to the application specific settings to ignore touch input while that application is active.
They responded it may appear in the next driver version.

@redphantom after the last update when they made separate process available for Superfly, it was discovered that render times are much slower with it checked (Superfly) I have it turned off on my system.

@F_Verbaas
Yes I have a Wacom Pen&Touch. But I do not start the render with it. In poser I only work with the mouse.@ghostship
Yes I also habe the problemwith the mouse by-itself-double-click of the mouse when I click on anything in the libery.

Yes, before I made the last update I also get stuck at starting. Since I made the update I get the stuck while it's loading the maps or updating objects.
but I never get a stuck as soon as it's path tracing. from this point it works perfectly.

but since I do not switch to another software while it's loading the render process. I think it does not happen so often.

I also have unchecked the tablet mode and scroll zoom now and I give attention to not touching the WACON while it's loading the render process....